The present invention is related to an electronic digital stop watch which is designed to measure duration of time by an electronic means from the moment the watch is triggered to start its time-keeping operation, and which has a function to display the time from the moment the watch is triggered to start its time-keeping operation.
Stop watches are useful timepieces for highly precisely measuring the times of various movements and are widely used for measuring the times of athletic events. In many cases, for example, when used for measuring the times of track events, the stop watches are used in a manner that a start button of the stop watch is pushed simultaneously with the sign of start to trigger its time-keeping function, and the start button is pushed again when a runner reaches the goal to stop the operation of a time-keeping mechanism, whereby the stop watch displays the duration of time which it has measured. So far as they are used in the aforementioned manner, the stop watches irrespective of whether they are of a mechanical type or of an electronic type, do not impose any particular inconvenience. However, when ordinary stop watches are used for measuring the times of events such as soccer, basketball, and the like which are carried out within predetermined periods of time, the umpires must frequently consult the display of the stop watch as the remaining duration of time approaches the finish time to know the exact finish time. The consultation of the stop watch will further involve difficulty in case there developed loss times due to violation of the rules during the event. This difficulty inherent in the conventional stop watches also holds true when stop watches are used for other applications than the athletic events, such as measurement of times associated with physical and chemical experiments which are often carried out within predetermined periods of time.